How can you harness chikungunya and dengue through an integrated environment safe approach?

Answer 1

HARNESSING CHIKUNGUNYA & DENGUE- AN INTEGRATED ENVIRONMENT SAFE APPROACH * Sreejith A., **Dr. Lakshmanan S Recent outbreaks and resurgence of mosquito-borne diseases such as Chickungunya and dengue in parts of Indian peninsula, especially in state of Kerala, which boasts an efficient healthcare system, is an outcome of extensive mosquito breeding under situations of unsustainable environment management. Chikungunya is a relatively rare form of viral fever caused by an RNA virus, alphavirus (Fam:Togoviridae) that is spread by mosquito bites from Aedes aegypti mosquitoes, though recent research by the Pasteur Institute in Paris claims the virus has suffered a mutation that enables it to be transmitted by Aedes aegypti , Aedes albopictus (Tiger mosquito). Dengue Fever (DF), an outbreak prone viral disease is transmitted by Aedesmosquitoes. DF is characterized by fever, headache, muscle and joint pains, rash, nausea and vomiting. Some infection results in Dengue Haemorrhagic Fever (DHF) - a syndrome that in its severe form can threaten the patient's life primarily through increased vascular permeability and shock. The four-dengue viruses DEN 1, 2, 3 and 4, which are closely related antigenically, causes DF and DHF. Aedes aegypti is the main vector species of DF/DHF in India and is common in most of the urban areas on account of deficient water management, presence of nondegradable tyres and long-lasting plastic containers as well as increasing urban agglomerations and inability of the public health community to mobilize the population to respond to the need to eliminate mosquito breeding sites. Overhead tanks, ground water storage tanks and septic tanks are usually the primary habitats where the Aedes sp. breeds almost entirely. Natural larval habitats are rare, but include tree holes, leaf axles and coconut shells. The population of Aedes aegypti fluctuates with rainfall temperature and humidity. Under the optimal conditions the life cycle of aquatic stage of the Aedes aegypti (the time taken from hatching to adult emergence) can be as short as seven days. At low temperatures, however, it may take several weeks for adults to emerge. With the rise in global temperature as a result of Global climate change, which is evident during the past two months in the state of Kerala, may be one of the many reasons for extensive multiplication of arthropod vectors like Aedes sp. During the rainy season, when survival is longer, the risk of virus transmission is greater. The rural spread of Aedes is a relatively recent occurrence associated with expanding network of rural water supply schemes and other development projects without health and environmental impact assessments, scarcity of water with consequent water storage, changing lifestyle with improper use of air coolers and indiscriminate use of disposable containers, bottles, etc, increased the spread. Therefore, the key to control vector borne diseases is adoption of a comprehensive approach by way of regular vector surveillance and integrated management of the Aedes mosquitoes through environmental, biological and chemical control that are safe and cost effective; Environmental Management The major environmental management methods used for control of immature stages of Aedes sp. is: * Environmental modification: Long lasting physical transformation of vector habitats. * For example, improved water supply, mosquito proofing of overhead tanks, cisterns or underground reservoirs. * Environmental manipulation: Temporary changes to vector habitats that involve the management of essential. and non-essential. containers and management of or removal of natural breeding sites. * Changes in human habitations: Efforts are made to reduce man-virus contact by mosquito proofing of houses with screens on doors/windows. Biological Control * Larvivorous fish are recommended for control of Aedes aegypti in large water bodies or large water containers. * Endotoxin-producing bacteria, Bacillus thuringiensis (Bt) serotype H-14 (Bt H-14) has been found an effective mosquito control agent. Management at Household, Community and Institutional Level: Aedes aegypti mosquito bites during daytime. Adult mosquitoes should be killed by using of commercially available safe aerosols (Pyrethroid-based). Rooms including closets, bathrooms and kitchens should be sprayed (by removing/covering all food items properly) for a few minutes and closing the room for 15-20 minutes. The timing of the spray should coincide with the peak biting time of the Aedes aegyptimosquito, e.g., early morning or late afternoon. * Taking personal protection measures like wearing protective clothing (full sleeved shirts & full pants during day time) and using mosquito nets, preferably insecticide treated ones, while sleeping, even during daytime. * Using commercially available repellents during daytime. * Using mosquito repellents or burning neem leaves, coconut shells and husk to kill or repel the mosquitoes. * Using tight-fitting screens/wire mesh on doors and windows. * Covering all water containers in the house and water storage structures to prevent fresh egg laying by the vector. * Emptying, drying water tanks, containers, coolers, bird baths, pets water bowls, plant pots, drip trays at least once each week. * Regularly checking for clogged gutters and flat roofs that may have poor drainage. * Launch awareness campaigns on vector borne diseases and seek cooperation for prevention of mosquito breeding and protection from mosquito bites. * Keeping the surroundings clean and improving basic sanitation measures. * Cleaning weeds and tall grass to reduce available outdoor resting places for adult mosquitoes near houses. * In case water containers cannot be emptied, applying Temephos (1 ppm) on weekly basis in coordination with the Health authorities. * Introducing Bacillus thuringiensis (Bt) dunks, larvivorous fishes (e.g., Gambusia / Guppy) in abandoned water bodies and ponds. * Carrying out Indoor Space spraying with Pyrethrum 2%. The timing of the spray should coincide with the biting time of the Aedes aegypti mosquito, e.g., early morning or late afternoon. * Carrying out fogging or Ultra Low Volume (ULV) spray by using 95% or pure technical malathion. = Conclusion = It is essential to built public-private partnership of hospitals, non-health sector departments including schools/colleges, civil society organizations (NGOs, Faith Based Organizations and Community Based Organizations like Residents Welfare Organizations, Self-Help Groups), Panchayati Raj Institutions/Municipal Bodies or such like local self-governments, local Religious Bodies, Nehru Yuvak Kendras, NSS/NCC units in schools and colleges as well as professional associations and corporate sector to accomplish successful vector control programme on a sustainable basis. References Guidelines For Integrated Vector Management For Control Of Dengue / Dengue Haemorrhagic Fever, NVBDCP, Delhi HHS Publication No. (CDC) (99-xxxx) U.S. Department of Health and Human Services Public Health Service Lumsden WHR (1955). "An Epidemic of Virus Disease in Southern Province, Tanganyika Territory, in 1952-53; II. General Description and Epidemiology". Trans Royal Society Trop Med Hyg 49 (1): 33-57. Robinson Marion (1955). "An Epidemic of Virus Disease in Southern Province, Tanganyika Territory, in 1952-53; I. Clinical Features". Trans Royal Society Trop Med Hyg 49 (1): 28-32. Vanlandingham DL, Hong C, Klingler K, Tsetsarkin K, McElroy KL, Powers AM, Lehane MJ, Higgs S (2005). "Differential infectivities of o'nyong-nyong and chikungunya virus isolates in Anopheles gambiae and Aedes aegypti mosquitoes". Am J Trop Med Hyg 72 (5): 616-21. PubMed. *Author is currently working as Project Officer, World Wide Fund for Nature - India ** Co-author is a practising Physician in Social and Preventive Medicine at PRS Hospital, Trivandrum. HARNESSING CHIKUNGUNYA & DENGUE- AN INTEGRATED ENVIRONMENT SAFE APPROACH * Sreejith A., **Dr. Lakshmanan S Recent outbreaks and resurgence of mosquito-borne diseases such as Chickungunya and dengue in parts of Indian peninsula, especially in state of Kerala, which boasts an efficient healthcare system, is an outcome of extensive mosquito breeding under situations of unsustainable environment management. Chikungunya is a relatively rare form of viral fever caused by an RNA virus, alphavirus (Fam:Togoviridae) that is spread by mosquito bites from Aedes aegypti mosquitoes, though recent research by the Pasteur Institute in Paris claims the virus has suffered a mutation that enables it to be transmitted by Aedes aegypti , Aedes albopictus (Tiger mosquito). Dengue Fever (DF), an outbreak prone viral disease is transmitted by Aedesmosquitoes. DF is characterized by fever, headache, muscle and joint pains, rash, nausea and vomiting. Some infection results in Dengue Haemorrhagic Fever (DHF) - a syndrome that in its severe form can threaten the patient's life primarily through increased vascular permeability and shock. The four-dengue viruses DEN 1, 2, 3 and 4, which are closely related antigenically, causes DF and DHF. Aedes aegypti is the main vector species of DF/DHF in India and is common in most of the urban areas on account of deficient water management, presence of nondegradable tyres and long-lasting plastic containers as well as increasing urban agglomerations and inability of the public health community to mobilize the population to respond to the need to eliminate mosquito breeding sites. Overhead tanks, ground water storage tanks and septic tanks are usually the primary habitats where the Aedes sp. breeds almost entirely. Natural larval habitats are rare, but include tree holes, leaf axles and coconut shells. The population of Aedes aegypti fluctuates with rainfall temperature and humidity. Under the optimal conditions the life cycle of aquatic stage of the Aedes aegypti (the time taken from hatching to adult emergence) can be as short as seven days. At low temperatures, however, it may take several weeks for adults to emerge. With the rise in global temperature as a result of Global climate change, which is evident during the past two months in the state of Kerala, may be one of the many reasons for extensive multiplication of arthropod vectors like Aedes sp. During the rainy season, when survival is longer, the risk of virus transmission is greater. The rural spread of Aedes is a relatively recent occurrence associated with expanding network of rural water supply schemes and other development projects without health and environmental impact assessments, scarcity of water with consequent water storage, changing lifestyle with improper use of air coolers and indiscriminate use of disposable containers, bottles, etc, increased the spread. Therefore, the key to control vector borne diseases is adoption of a comprehensive approach by way of regular vector surveillance and integrated management of the Aedes mosquitoes through environmental, biological and chemical control that are safe and cost effective; Environmental Management The major environmental management methods used for control of immature stages of Aedes sp. is: * Environmental modification: Long lasting physical transformation of vector habitats. * For example, improved water supply, mosquito proofing of overhead tanks, cisterns or underground reservoirs. * Environmental manipulation: Temporary changes to vector habitats that involve the management of essential. and non-essential. containers and management of or removal of natural breeding sites. * Changes in human habitations: Efforts are made to reduce man-virus contact by mosquito proofing of houses with screens on doors/windows. Biological Control * Larvivorous fish are recommended for control of Aedes aegypti in large water bodies or large water containers. * Endotoxin-producing bacteria, Bacillus thuringiensis (Bt) serotype H-14 (Bt H-14) has been found an effective mosquito control agent. Management at Household, Community and Institutional Level: Aedes aegypti mosquito bites during daytime. Adult mosquitoes should be killed by using of commercially available safe aerosols (Pyrethroid-based). Rooms including closets, bathrooms and kitchens should be sprayed (by removing/covering all food items properly) for a few minutes and closing the room for 15-20 minutes. The timing of the spray should coincide with the peak biting time of the Aedes aegyptimosquito, e.g., early morning or late afternoon. * Taking personal protection measures like wearing protective clothing (full sleeved shirts & full pants during day time) and using mosquito nets, preferably insecticide treated ones, while sleeping, even during daytime. * Using commercially available repellents during daytime. * Using mosquito repellents or burning neem leaves, coconut shells and husk to kill or repel the mosquitoes. * Using tight-fitting screens/wire mesh on doors and windows. * Covering all water containers in the house and water storage structures to prevent fresh egg laying by the vector. * Emptying, drying water tanks, containers, coolers, bird baths, pets water bowls, plant pots, drip trays at least once each week. * Regularly checking for clogged gutters and flat roofs that may have poor drainage. * Launch awareness campaigns on vector borne diseases and seek cooperation for prevention of mosquito breeding and protection from mosquito bites. * Keeping the surroundings clean and improving basic sanitation measures. * Cleaning weeds and tall grass to reduce available outdoor resting places for adult mosquitoes near houses. * In case water containers cannot be emptied, applying Temephos (1 ppm) on weekly basis in coordination with the Health authorities. * Introducing Bacillus thuringiensis (Bt) dunks, larvivorous fishes (e.g., Gambusia / Guppy) in abandoned water bodies and ponds. * Carrying out Indoor Space spraying with Pyrethrum 2%. The timing of the spray should coincide with the biting time of the Aedes aegypti mosquito, e.g., early morning or late afternoon. * Carrying out fogging or Ultra Low Volume (ULV) spray by using 95% or pure technical malathion. = Conclusion = It is essential to built public-private partnership of hospitals, non-health sector departments including schools/colleges, civil society organizations (NGOs, Faith Based Organizations and Community Based Organizations like Residents Welfare Organizations, Self-Help Groups), Panchayati Raj Institutions/Municipal Bodies or such like local self-governments, local Religious Bodies, Nehru Yuvak Kendras, NSS/NCC units in schools and colleges as well as professional associations and corporate sector to accomplish successful vector control programme on a sustainable basis. References Guidelines For Integrated Vector Management For Control Of Dengue / Dengue Haemorrhagic Fever, NVBDCP, Delhi HHS Publication No. (CDC) (99-xxxx) U.S. Department of Health and Human Services Public Health Service Lumsden WHR (1955). "An Epidemic of Virus Disease in Southern Province, Tanganyika Territory, in 1952-53; II. General Description and Epidemiology". Trans Royal Society Trop Med Hyg 49 (1): 33-57. Robinson Marion (1955). "An Epidemic of Virus Disease in Southern Province, Tanganyika Territory, in 1952-53; I. Clinical Features". Trans Royal Society Trop Med Hyg 49 (1): 28-32. Vanlandingham DL, Hong C, Klingler K, Tsetsarkin K, McElroy KL, Powers AM, Lehane MJ, Higgs S (2005). "Differential infectivities of o'nyong-nyong and chikungunya virus isolates in Anopheles gambiae and Aedes aegypti mosquitoes". Am J Trop Med Hyg 72 (5): 616-21. PubMed. *Author is currently working as Project Officer, World Wide Fund for Nature - India ** Co-author is a practising Physician in Social and Preventive Medicine at PRS Hospital, Trivandrum.